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14#include <linux/cpu.h>
15#include <linux/err.h>
16#include <linux/hrtimer.h>
17#include <linux/interrupt.h>
18#include <linux/percpu.h>
19#include <linux/profile.h>
20#include <linux/sched.h>
21#include <linux/tick.h>
22
23#include <asm/irq_regs.h>
24
25#include "tick-internal.h"
26
27
28
29
30DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
31
32
33
34ktime_t tick_next_period;
35ktime_t tick_period;
36int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT;
37DEFINE_SPINLOCK(tick_device_lock);
38
39
40
41
42struct tick_device *tick_get_device(int cpu)
43{
44 return &per_cpu(tick_cpu_device, cpu);
45}
46
47
48
49
50int tick_is_oneshot_available(void)
51{
52 struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
53
54 return dev && (dev->features & CLOCK_EVT_FEAT_ONESHOT);
55}
56
57
58
59
60static void tick_periodic(int cpu)
61{
62 if (tick_do_timer_cpu == cpu) {
63 write_seqlock(&xtime_lock);
64
65
66 tick_next_period = ktime_add(tick_next_period, tick_period);
67
68 do_timer(1);
69 write_sequnlock(&xtime_lock);
70 }
71
72 update_process_times(user_mode(get_irq_regs()));
73 profile_tick(CPU_PROFILING);
74}
75
76
77
78
79void tick_handle_periodic(struct clock_event_device *dev)
80{
81 int cpu = smp_processor_id();
82 ktime_t next;
83
84 tick_periodic(cpu);
85
86 if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
87 return;
88
89
90
91
92 next = ktime_add(dev->next_event, tick_period);
93 for (;;) {
94 if (!clockevents_program_event(dev, next, ktime_get()))
95 return;
96
97
98
99
100
101
102
103
104
105 if (timekeeping_valid_for_hres())
106 tick_periodic(cpu);
107 next = ktime_add(next, tick_period);
108 }
109}
110
111
112
113
114void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
115{
116 tick_set_periodic_handler(dev, broadcast);
117
118
119 if (!tick_device_is_functional(dev))
120 return;
121
122 if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
123 !tick_broadcast_oneshot_active()) {
124 clockevents_set_mode(dev, CLOCK_EVT_MODE_PERIODIC);
125 } else {
126 unsigned long seq;
127 ktime_t next;
128
129 do {
130 seq = read_seqbegin(&xtime_lock);
131 next = tick_next_period;
132 } while (read_seqretry(&xtime_lock, seq));
133
134 clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
135
136 for (;;) {
137 if (!clockevents_program_event(dev, next, ktime_get()))
138 return;
139 next = ktime_add(next, tick_period);
140 }
141 }
142}
143
144
145
146
147static void tick_setup_device(struct tick_device *td,
148 struct clock_event_device *newdev, int cpu,
149 const struct cpumask *cpumask)
150{
151 ktime_t next_event;
152 void (*handler)(struct clock_event_device *) = NULL;
153
154
155
156
157 if (!td->evtdev) {
158
159
160
161
162 if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
163 tick_do_timer_cpu = cpu;
164 tick_next_period = ktime_get();
165 tick_period = ktime_set(0, NSEC_PER_SEC / HZ);
166 }
167
168
169
170
171 td->mode = TICKDEV_MODE_PERIODIC;
172 } else {
173 handler = td->evtdev->event_handler;
174 next_event = td->evtdev->next_event;
175 td->evtdev->event_handler = clockevents_handle_noop;
176 }
177
178 td->evtdev = newdev;
179
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182
183
184 if (!cpumask_equal(newdev->cpumask, cpumask))
185 irq_set_affinity(newdev->irq, cpumask);
186
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190
191
192
193 if (tick_device_uses_broadcast(newdev, cpu))
194 return;
195
196 if (td->mode == TICKDEV_MODE_PERIODIC)
197 tick_setup_periodic(newdev, 0);
198 else
199 tick_setup_oneshot(newdev, handler, next_event);
200}
201
202
203
204
205static int tick_check_new_device(struct clock_event_device *newdev)
206{
207 struct clock_event_device *curdev;
208 struct tick_device *td;
209 int cpu, ret = NOTIFY_OK;
210 unsigned long flags;
211
212 spin_lock_irqsave(&tick_device_lock, flags);
213
214 cpu = smp_processor_id();
215 if (!cpumask_test_cpu(cpu, newdev->cpumask))
216 goto out_bc;
217
218 td = &per_cpu(tick_cpu_device, cpu);
219 curdev = td->evtdev;
220
221
222 if (!cpumask_equal(newdev->cpumask, cpumask_of(cpu))) {
223
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226
227
228 if (!irq_can_set_affinity(newdev->irq))
229 goto out_bc;
230
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232
233
234
235 if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu)))
236 goto out_bc;
237 }
238
239
240
241
242
243 if (curdev) {
244
245
246
247 if ((curdev->features & CLOCK_EVT_FEAT_ONESHOT) &&
248 !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))
249 goto out_bc;
250
251
252
253 if (curdev->rating >= newdev->rating)
254 goto out_bc;
255 }
256
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259
260
261
262 if (tick_is_broadcast_device(curdev)) {
263 clockevents_shutdown(curdev);
264 curdev = NULL;
265 }
266 clockevents_exchange_device(curdev, newdev);
267 tick_setup_device(td, newdev, cpu, cpumask_of(cpu));
268 if (newdev->features & CLOCK_EVT_FEAT_ONESHOT)
269 tick_oneshot_notify();
270
271 spin_unlock_irqrestore(&tick_device_lock, flags);
272 return NOTIFY_STOP;
273
274out_bc:
275
276
277
278 if (tick_check_broadcast_device(newdev))
279 ret = NOTIFY_STOP;
280
281 spin_unlock_irqrestore(&tick_device_lock, flags);
282
283 return ret;
284}
285
286
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288
289
290
291static void tick_handover_do_timer(int *cpup)
292{
293 if (*cpup == tick_do_timer_cpu) {
294 int cpu = cpumask_first(cpu_online_mask);
295
296 tick_do_timer_cpu = (cpu < nr_cpu_ids) ? cpu :
297 TICK_DO_TIMER_NONE;
298 }
299}
300
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306
307
308static void tick_shutdown(unsigned int *cpup)
309{
310 struct tick_device *td = &per_cpu(tick_cpu_device, *cpup);
311 struct clock_event_device *dev = td->evtdev;
312 unsigned long flags;
313
314 spin_lock_irqsave(&tick_device_lock, flags);
315 td->mode = TICKDEV_MODE_PERIODIC;
316 if (dev) {
317
318
319
320
321 dev->mode = CLOCK_EVT_MODE_UNUSED;
322 clockevents_exchange_device(dev, NULL);
323 td->evtdev = NULL;
324 }
325 spin_unlock_irqrestore(&tick_device_lock, flags);
326}
327
328static void tick_suspend(void)
329{
330 struct tick_device *td = &__get_cpu_var(tick_cpu_device);
331 unsigned long flags;
332
333 spin_lock_irqsave(&tick_device_lock, flags);
334 clockevents_shutdown(td->evtdev);
335 spin_unlock_irqrestore(&tick_device_lock, flags);
336}
337
338static void tick_resume(void)
339{
340 struct tick_device *td = &__get_cpu_var(tick_cpu_device);
341 unsigned long flags;
342 int broadcast = tick_resume_broadcast();
343
344 spin_lock_irqsave(&tick_device_lock, flags);
345 clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_RESUME);
346
347 if (!broadcast) {
348 if (td->mode == TICKDEV_MODE_PERIODIC)
349 tick_setup_periodic(td->evtdev, 0);
350 else
351 tick_resume_oneshot();
352 }
353 spin_unlock_irqrestore(&tick_device_lock, flags);
354}
355
356
357
358
359static int tick_notify(struct notifier_block *nb, unsigned long reason,
360 void *dev)
361{
362 switch (reason) {
363
364 case CLOCK_EVT_NOTIFY_ADD:
365 return tick_check_new_device(dev);
366
367 case CLOCK_EVT_NOTIFY_BROADCAST_ON:
368 case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
369 case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
370 tick_broadcast_on_off(reason, dev);
371 break;
372
373 case CLOCK_EVT_NOTIFY_BROADCAST_ENTER:
374 case CLOCK_EVT_NOTIFY_BROADCAST_EXIT:
375 tick_broadcast_oneshot_control(reason);
376 break;
377
378 case CLOCK_EVT_NOTIFY_CPU_DYING:
379 tick_handover_do_timer(dev);
380 break;
381
382 case CLOCK_EVT_NOTIFY_CPU_DEAD:
383 tick_shutdown_broadcast_oneshot(dev);
384 tick_shutdown_broadcast(dev);
385 tick_shutdown(dev);
386 break;
387
388 case CLOCK_EVT_NOTIFY_SUSPEND:
389 tick_suspend();
390 tick_suspend_broadcast();
391 break;
392
393 case CLOCK_EVT_NOTIFY_RESUME:
394 tick_resume();
395 break;
396
397 default:
398 break;
399 }
400
401 return NOTIFY_OK;
402}
403
404static struct notifier_block tick_notifier = {
405 .notifier_call = tick_notify,
406};
407
408
409
410
411
412
413void __init tick_init(void)
414{
415 clockevents_register_notifier(&tick_notifier);
416}
417